(a) Technical Field
The present disclosure relates to a backlight assembly that removes dark areas, and more particularly, to a backlight assembly from which dark areas occurring in a light guiding plate (LGP) are removed when light is guided by the LGP and a display device provided with the backlight assembly.
(b) Discussion of the Related Art
Liquid crystal display (LCD) devices have decreased in size and weight and exhibit enhanced performance. As a result, demand for such display devices has increased.
LCD devices employing an LCD panel are small in size and weight, and consume low power. LCD devices are used in almost all information processing apparatuses requiring a display device and have become attractive as a substitute for cathode ray tubes (CRTs).
LCD devices change a molecular alignment of liquid crystal to different molecular alignments with the application of a voltage. As a result of the change in molecular alignment, a change in optical characteristics, such as birefringence, optical rotary power, dichroism, and optical scattering, of liquid crystal cells emitting light results in a visual change. That is, LCD devices are light receiving display devices which display data using modulation of light in the liquid crystal cells.
Specifically, small-sized LCD devices, such as displays on mobile phones, employ a light emitting diode (LED) with small volume, high emission efficiency, minimized power consumption, and strong resistance to outside impacts.
Light emitted from the LED is received and guided by the LGP and is supplied to an LCD panel built into the LCD device. Since the LED is a point light source, dark areas are generated between LEDs at an inlet of the LGP when the light emitted from the LEDs is incident on the LGP. For example, assuming the LGP is made of polymethyl methacrylate (PMMA) having a refractive index n of 1.49, when the light emitted from the LEDs having light directivity of 60° is incident from the air to the LGP, the light is incident on the LGP at an incidence angle of 35.5° by Snell's law.
At this incidence angle, dark areas are generated between the light emitting diodes, thereby deteriorating the light emission efficiency. The dark areas are generated at the edges of the LCD device, resulting in a screen that is dark and unable to show a clear image.